I'm not sure how technical you are (this isn't a simple subject to implement), but I'd look into "managed switches" (to enable classifying traffic from specific

I'm not sure how technical you are (this isn't a simple subject to implement), but I'd look into "managed switches" (to enable classifying traffic from specific ports, aka one the TV is plugged into), "VLANs" (what the switch uses to "segregate" traffic), "policy based firewall" (allow you to be explicit in what traffic is allowed or not, two examples you might look into being pfsense and mikrotik).